1. Field of the Invention
This invention relates to filters for detectors (e.g., semiconductor device detectors).
2. Description of the Related Art
(Note: This application references a number of different publications as indicated throughout the specification by one or more reference numbers within brackets, e.g., [x]. A list of these different publications ordered according to these reference numbers can be found below in the section entitled “References.” Each of these publications is incorporated by reference herein.)
The detection of ultraviolet (UV) light has applications in planetary imaging and spectroscopy, astronomy, communications, and medical imaging/diagnostics. One major challenge facing UV detection is visible or solar rejection, as UV photons in bands of interest are often greatly outnumbered by visible photons, effectively reducing the signal-to-noise ratio. One approach to selective UV detection is the use of wide bandgap semiconductors. These materials are inherently insensitive to lower-energy photons, but device performance is typically limited by material quality issues that degrade quantum efficiency in the ultraviolet. Si sensors can be modified, through a technique invented at the Jet Propulsion Laboratory (JPL) called delta-doping, to have 100% internal quantum efficiency throughout the ultraviolet [1], but this high efficiency is maintained throughout the visible as well.